Oracle Blog

Chris Gerhard's Weblog

Thursday Dec 27, 2007

Following on from my earlier ethernet
over mains post I have now purchased enough ethernet over mains
bricks to from two separate networks one for each fuse box and each
network now claims 85Mbits/sec. So currently I have:

Which is less than ideal as the picture frame Sun Ray is connected
via two Ethernet over mains hops and one of those is shared with
another Sun Ray however until the rest of the house moves are done it
works. At that point the switch will live where the Hub currnetly is
so no Sun Ray will be more than one “mains hop” away from
the server. The picture in the frame refreshes in about 2 seconds
which is o.k and it is not loosing the connection to the Sun Ray
server, which means it has returned to being a practical solution.

The ethernet over mains bricks coped
much worse when there was one on one fuse box and two on the other
compared to when there were just two bricks one on each fuse box.

1If
ascii art is good enough ascii art will do. The answer is invariably
wanted as fast as possible, pretty does not make it more right.

Wednesday Dec 19, 2007

Since the whole house is not wired with Cat 5 cable I have had to
use Mains over ethernet to provide some networking. However after our
building works the mains in our house is now split in two with two
fuse boxes (containing circuit breakers and RCDs) which then have
separate tails leading to the electricity board fuse.

1Needless
to say the computer that drives the Sun Rays is on one mains fuse box
and the Sun Ray in the kitchen is on the other.

You can see the effect of the extra hop in the screen shot. Rather
than the maximum 85Mbps when the two mains bricks are on the same
fuse box that reduces to a paltry 13 Mbps thanks to the hop to the
Electricity board fuse and back. This explains why that Sun Ray photo
frame sometimes looses connection with the server when updating the
picture. The other Sun Ray in Sues Office works like a dream2.

Clearly using these to form a network between buildings would not
fly. That does however not stop me from being paranoid enough to have
blotted out the ethernet addresses and passwords from the screen
shot.

I can see that if in the final network set up I have to have
devices on both fuse boxes I will have to run them as separate
networks which will cost me one extra mains over ethernet brick.

1Yes
this is a windows only application. However I did grab this screen
shot using a VNC session on Solaris.

2Except
when the server will occasionly on booting negotiate the ethernet
switch down to 100Mbs rarther than 1Gb at which point things are
much more sluggish, so I have a cron job that checks the speed and
warns me of this.